Device for plugging a threaded collar using a cap with a tamperproof ring

ABSTRACT

The tamperproof closing device for a receptacle having a threaded collar comprises a screw cap ( 1 ) consisting of a bottom ( 8 ) and a cylindrical skirt ( 9 ) having inner threading for co-operation with the corresponding threading ( 5 ) on the collar ( 2 ) and extended by a tamperproof ring ( 13 ) which is attached by frangible means ( 20 ). The collar has a plurality of outer radial notches arranged at the base thereof. Said notches are circumferentially oriented and the ring comprises a plurality of inner radial reliefs ( 15 ) whose profile is complementary to that of the notches ( 7 ). The orientations and dimensions of the notches ( 7 ) and reliefs ( 15 ) are determined in such a way that the second items can pass onto the first items in the direction of screwing as a result of elastic deformation of the constitutive material and can prevent the same from occurring in the opposite direction. The reliefs ( 15 ) are formed on an annular lip ( 14 ) which is turned back and originates from the tamperproof ring ( 13 ). When it leaves the mould, said lip ( 14 ) forms an annular truncated appendix converging slightly towards the inside and bearing the reliefs on the outside ( 15 ).

[0001] The present invention relates to a tamperproof closure device fora receptacle with threaded collar (which is directly formed on thereceptacle or is added thereto) comprising a screw cap presenting abottom and a cylindrical skirt internally threaded to cooperate with thecorresponding thread made on the collar, and extended by a tamperproofring attached by frangible means, the collar presenting at its base aplurality of outer radial notches oriented circumferentially and thering presenting a plurality of inner radial reliefs whose profile iscomplementary to that of the notches, the orientations and thedimensions of the notches and of the reliefs being determined so as toallow the passage of the latter on the former in the direction ofscrewing thanks to the elastic deformation of the constituent material,and to oppose this passage in the opposite direction. This deformationmakes it possible to position the cap and its tamperproof ring byscrewing. In the event of opening or attempt to open the cap byunscrewing, the reliefs of the tamperproof ring abut on the notches andoppose rotation of the ring, in which case their frangible links withthe skirt of the cap break.

[0002] Such a device is well known in the prior art and is illustratedfor example in document EP 0 261 037A. Similar devices are currentlyused in the food industry, particularly for drinks, as described in EP 0330 964. In numerous cases, it is important to guarantee not only thatthe cap has not been opened and the contents of the recipient emptied ormodified, but also that the asepsis of the packaging has been conserved.Now, in certain devices, this asepsis can be interrupted even withoutbreaking the tamperproof ring, as a very slight unscrewing of the capthrough an angle of a few degrees (for example 5°), which is generallyinsufficient to provoke with certainty the abutment of the reliefs ofthe cap against the notches of the collar and the rupture of thefrangible links (in certain devices on the market, the cap must beunscrewed through at least 90° before the tamperproof ring is broken),but may be sufficient to destroy the tightness and asepsis of theclosure. It is therefore important to design a closure device whichmakes it possible to solve this problem without excessive complicationof construction.

[0003] On the other hand, in the known devices, the reliefs of the ringmust be moulded inside it, which complicates moulding of the cap andincreases the cost price thereof, especially if it is desired to adaptthe notches and the reliefs to the solution of the problem of asepsismentioned above.

[0004] It is an object of the invention to propose a closure structureof the general type described hereinabove, which can be moulded andunmoulded more easily and thus allow the cost price of the cap to bereduced without sacrificing the quality of the closure; on the contrary.

[0005] The object of the invention is attained in that the inner reliefsof the tamperproof ring are no longer formed directly on its innerperiphery but on an annular lip which is turned back and originates fromthe ring, this lip forming, when it leaves the mould, an annulartruncated appendix converging slightly towards the inside and bearingthe reliefs on the outside, while it is provided to space the reliefs ofthe ring and the notches of the collar apart by different pitches p andq, chosen to ensure the engagement of at least one notch with at leastone relief, with an angular periodicity a preferably less than 3°. Inthat case, it is easy to form the reliefs by moulding outside the lipbefore turn-back, at the same time as the cap itself is moulded, and toproceed with turning back the lip preferably prior to positioning thecap on the collar. Such a lip with turn back attached to a tamperproofring is known per se (cf. for example document FR 2 768 131 A, lip 31),but it was used up to now only for axially locking the tamperproof ringunder a counter-ring of the collar. One advantage resulting from theplacing of the reliefs on the lip with turn-back comes from thesuppleness of the latter and from its facility of deformation whichrenders the screwing operation of the cap easier because the screwingcouples are reduced. The continuous nature of the lip induces a circulardistribution of an effort of radial expansion undergone by the lip inthe event of a fraudulent attempt being made to open the cap. Thanks tothe increased simplicity in manufacturing the cap of the invention, itis possible to more easily adapt the notches and relief so as better toguarantee the asepsis of the closure, even for very small angles ofunscrewing, for example of the order of 3°.

[0006] Advantageously, the values of pitches p and q differ from oneanother by said angle a, a being a sub-multiple of the pitches p and qof said reliefs and notches (i.e. p=m×a and q=n×a, m and n being wholenumbers with m−n=+/−1), with the result that, with this angularperiodicity a, there is always at least one and preferably twoengagements between notches and reliefs, the other notches and reliefsin that case not being engaged. The value of a is chosen to be low, forexample less than 3° to ensure that the angle of unscrewing which bringsabout rupture of the tamperproof ring will be less than a value (forexample 3°) which would lead to the loss of asepsis.

[0007] The notches and the reliefs are advantageously formed on only apart of the periphery of the collar and of the tamperproof ring,preferably substantially on two opposite quadrants.

[0008] Other advantages and characteristics of the invention will beevident on reading the following description with reference to theaccompanying drawings, in which:

[0009]FIG. 1 shows in perspective with parts torn away, a form ofembodiment of a closure according to the invention screwed on itscollar.

[0010]FIGS. 2 and 3 schematically show in radial section the skirt withreliefs according to the invention, respectively before and afterturn-back.

[0011]FIG. 4 is a schematic plan view showing the cooperation of thereliefs of the skirt of FIGS. 2 and 3 with the collar with which theclosure fits.

[0012]FIG. 5 shows the collar of the closure of FIG. 1 in perspective.

[0013]FIG. 6 shows the closure itself of FIG. 1, in perspective.

[0014]FIG. 7 shows the closure and the collar, in section in plane E-Eof FIG. 1.

[0015]FIG. 1 shows a cap 1 intended to be screwed on the collar 2 of areceptacle.

[0016] The collar 2 (cf. FIGS. 1, 5 and 7) comprises a cylindricalsection 3 rising from an annular edge 4 The section 3 bears on the upperpart of its outer periphery a thread 5 for screwing, and, on the lowerpart of this periphery, an annular rib 6 below which are formedprojections 7 forming notches, distributed over the periphery or only apart thereof (substantially on two opposite quadrants in the example ofembodiment illustrated).

[0017] The cap, moulded for example from polyethylene (PE), comprises(cf. FIGS. 1, 6 and 7) a bottom 8 from which issues a cylindrical outerskirt 9 comprising on its outer periphery flutings for gripping orsimilar reliefs 10 and on its inner periphery a screw thread 11 intendedto cooperate with the thread 5 of the collar 2. The flutings 10 stop atthe level of an annular excess thickness 12 below which is formed thetamperproof device comprising a tamperproof ring 13 attached to theskirt by breakable bridges 20. Issuing from the ring 13, the turned backlip 14 bears reliefs 15 which are oriented radially towards the inside(after turn-back of said lip) and cooperate with the notches 7 of thecollar 2 in order to prevent rotation of the cap 1 on the collar 2. Theturned back lip 14 is housed beneath the annular rib 6 of the collar. Inmanner known per se, the cap also comprises, issuing from the bottom 8,a sleeve 21 for tightness cooperating with the interior of the collar 2.

[0018]FIG. 2 schematically shows the position of the lip 14 at thebottom of the ring 13 on leaving the mould, the lip 14 in that caseforms a supple, annular, truncated appendix converging slightly towardsthe inside and bearing the reliefs 15 outside. The lip 14 convergestowards the bottom of FIG. 2, i.e. opposite the bottom 8 of the cap.When the cap is being placed on the collar, the lip is turned back asknown per se, which has the effect of exposing its reliefs 15 oppositethe notches 7 of the collar 2 (which has been shown as formed directlyon the receptacle in FIG. 3).

[0019]FIG. 4 very schematically shows the functioning and cooperation ofthe reliefs 15 with the notches 7. Only four pairs of reliefs andnotches in mesh have been shown for simplification. These pairs functionlike pawls in order to prevent rotation of the cap on the collar in thedirection of unscrewing but to allow the initial screwing thanks to thecooperation of the ramps formed on the notches and the reliefs.

[0020] In fact and as illustrated precisely in FIG. 7, it is preferredto arrange the notches 7 and the reliefs 15 in a sufficient number toallow an engagement of the notches and the reliefs at regular and nottoo large angles (in order to preserve safety from asepsis);arrangements are such that the reliefs 15 do not all engage at the sametime with all the notches 7, in order to avoid the burst of the capwhich might result when all the reliefs overlap all the notches and tominimise the frictions. Finally, the respective pitch of the notches andthe reliefs is different and calculated so as to make it possible toensure an engagement of notches and of reliefs at a small pitch equal tothe difference of the respective pitches. As the example of FIG. 7shows, while the notches 7 are formed regularly every 10° (over twoopposite quadrants of the collar), the reliefs 15 are formed with anglesof 12.5°. More precisely, the collar comprises over a little more than aquadrant nine notches 7 a to 7 i, formed identically from a ramp 16 anda stop face 17 except for the notch 7 b whose ramp is longer; theconsecutive stops are spaced apart by 10° except between the stop facesof the first two notches 7 a, 7 b where the angular space is 20°. Thecap comprises a first relief 15 a extending over 10° and followed byeight reliefs 15 b to 15 h extending over 12.5°, said reliefs all alsocomprising a ramp 18 and a stop face 19. In the position shown in FIG.7, it is seen that only the stop faces of couples 7 a, 15 b and 7 e, 15f are in abutment, while the other pairs cannot coincide and willtherefore bring about a slight expansion of the cap at their level. Asmay be seen in FIG. 7, the following engagement, if one continued toscrew the stopper on the collar, would be 7 d with 15 e (after a pitchof 2.5°), then 7 c with 15 d, then 7 b with 15 c. In this way, the pitchp of the reliefs is 12.5°, the pitch q of the notches is 10°, and thepitch a which results therefrom for the engagements between notches andreliefs is 2.5°. The notch 7 with longer ramp tends to retain the cap tothe rear and therefore to reduce the clearance of the cap on the collar.

1. Tamperproof closure device for a receptacle with threaded collarcomprising a screw cap (1) presenting a bottom (8) and a cylindricalskirt (9) internally threaded to cooperate with the corresponding thread(5) made on the collar (2), and extended by a tamperproof ring (13)attached by frangible means (20), the collar presenting at its base aplurality of outer radial notches (7) oriented circumferentially and thering presenting a plurality of inner radial reliefs (15) whose profileis complementary to that of the notches, the orientations and thedimensions of the notches (7) and of the reliefs (15) being determinedso as to allow the passage of the latter on the former in the directionof screwing thanks to the elastic deformation of the constituentmaterial, and to oppose this passage in the opposite direction, saidreliefs (15) being formed on an annular lip (14) which is turned backand originates from the tamperproof ring (13), characterized in thatsaid lip forms, when it leaves the mould, an annular truncated appendixconverging slightly towards the inside and bearing the reliefs (15) onthe outside, and in that the notches (7) and the reliefs (15) are formedwith different respective pitches q and p such that they ensure theengagement of at least one notch (7 a) with at least one relief (15 b)with an angular periodicity a preferably less than 3°.
 2. Deviceaccording to claim 1, characterized in that the reliefs (15) are formedby moulding on the outside of the lip (14) before turn-back.
 3. Deviceaccording to either one of the preceding claims, characterized in thatthe notches (7) and the reliefs (15) are formed on only a part of theperiphery of the collar (2) and of the tamperproof ring (14), preferablysubstantially over two opposite quadrants.
 4. Device according to anyone of the preceding claims, characterized in that the pitches p and qare whole multiples of the periodicity of engagement a and differ fromone another by the value a.
 5. Device according to claim 4,characterized in that the respective pitches of the notches (7) and ofthe reliefs (15) are such that they ensure the engagement of at leastone notch (7 a) with at least one relief (15 b) with a periodicity apreferably less than 3°.
 6. Device according to claim 5, characterizedin that the pitches p and q are whole multiples of the periodicity ofengagement a and differ from one another by the value a.